The 'Traffic Box' displayed at a news conference Wednesday in Philadelphia

Stephanie Farr / Twitter

For reference, that’s 38th Street to the west, South Street to the south, the Delaware River to the east and Girard to Ridge to Spring Garden to the north. Major road closures will go into effect, too, including I-76, I-95, US-1, and 676.

In two news conferences over the last two weeks, Mayor Michael Nutter has encouraged residents to compare plans for the National Special Security Event to a huge snowstorm. On Thursday, the mayor’s spokesperson, Mark McDonald, confirmed the no-ticket, tow-first plan, characterizing it as nothing more than what would occur during a snow emergency. Vehicles parked on “authorized access roads” (thoroughfares highlighted in yellow on the above map, released yesterday) would be subject to impoundment.

“Of course, any illegally parked vehicle is subject to removal,” McDonald wrote in an email to Billy Penn. “The city will alert residents that they will need to move their cars during the papal visit. If not moved, they will be towed. Elsewhere in the Traffic Box, regular parking rules are in effect.”

What that means: The Philadelphia Parking Authority will not issue a ticket to a car that’s illegally parked, as it would under non-blizzard circumstances. Instead, the car will be towed.

Philadelphia Parking Authority spokesperson Martin O’Rourke, who confirmed that the PPA is in the loop regarding papal security, denied having any knowledge of the plan. How will this towing plan be implemented? According to one law enforcement official Billy Penn spoke to on condition of anonymity, it is not clear. That’s because residents will be allowed to drive vehicles within the security perimeter — a clear departure from last week, when Billy Penn reported that officials had planned for no vehicular traffic within “the box.”

Another official familiar with advance planning for the Pope’s visit worried if officials follow through on the towing measure, it would incur a “citywide mutiny” – which may be why no mention of impounding was made during yesterday’s press conference.

But considering the high-profile nature of the Pope’s visit, which is designated by local, state, and federal officials as a National Special Security Event, towing illegally-parked cars isn’t a huge hurdle. After all, the Secret Service’s security plans already include deploying 1,000 State Police troopers throughout the city, closing the Ben Franklin Bridge to vehicular traffic, shutting down most regional rail and city train stops, and putting the National Guard on standby.